Shape-memory effect in PLZT ferroelectric ceramics

The shape-memory effect in PLZT (Lead Lanthanum Zirconate Titanate) ceramics with composition x/65/35 (4.0  x  8.0) has been investigated using bending experiments and temperature cycling. Relationships between load and the degree of bending, together with their temperature dependence, have been determined, and characteristic temperatures associated with the onset and disappearance of the pseudo-plastic shape change are compared with the observed dielectric anomalies. Effects of mechanical stress and electric field on the shape-memory temperatures and the magnitude of strain have also been investigated. It is concluded that domain alignment and the temperature-dependence of spontaneous strain are important factors governing the shape-memory effect in ferroelectrics. Preferred-orientation effects have been confirmed by X-ray diffraction analysis.